Consider the case where we have a rectangle of side lengths 2x + 3 and 3x + 1, as shown in the figure. Class 9
Consider the case where we have a rectangle of side lengths 2x + 3 and 3x + 1, as shown in the figure. Class 9
Question 1.
Consider the case where we have a rectangle of side lengths 2x + 3 and 3x + 1, as shown in the figure. What can you say about its area (2x + 3) (3x + 1)? Class 9

Fill in the blanks with the appropriate expressions to make the equation true. (px + a) (qx + b)
= (___) x² + (____) x + _________ .
Also, verify your answer using the distributive property
Answer:
i. The rectangle has side lengths 2x + 3 and 3x + 1.
The area of the rectangle is:
(2x + 3)(3x + 1) sq. units
Using algebra tiles, the rectangle consists of:
a. six x² - tiles (2x × 3x = 6x²)
b. eleven x-tiles
(2x × 1 + 3 × 3x = 2x + 9x = 11x)
c. three unit tiles (3 × 1 = 3)
Area = (2x + 3)(3x + 1) = 6x2 + 11x + 3
ii. (px + a)(qx + b) = (pq)x² + (pb + aq)x + ab
Verification:
(px + a)(qx + b) = px(qx + b) + a(qx + b)
= pqx² + pbx + aqx + ab
= pqx² + (pb + aq)x + ab